This invention relates to a generator regulator having a microprocessor. This invention further relates to a generator regulator which generates a control signal as a function of the microprocessor comparison of various sensed parameters for controlling the electrical output from the generator.
It is widely known that the electrical outputs of generators, including alternators, are regulated to establish and maintain certain output parameters, such as voltage, frequency and/or current, generally constant notwithstanding fluctuations in the load, temperature, input voltage and the like.
The majority of present voltage regulating systems utilize analog circuitry. Such systems include transformer systems having a voltage sensing device to monitor the output and send a signal to a control circuit, an amplifying section which conditions the signal, and a circuit which responds to the signal by increasing or decreasing the control signal. These changes in the control signal are accomplished by electromechanical means or by an electronic power control circuit. Present regulators, even those with digital circuitry, are incapable of performing diverse functions such as controlling VAR levels, maintaining a constant power factor and maintaining a constant voltage through a single regulator.
Presently available single phase regulators may be connected in a three phase configuration yet are not capable of automatically compensating when switching between single phase and three phase electrical outputs.
Voltage regulators currently employ motorized variable resistors for adjustment. In a system having, e.g., a synchronizer, adjustments will be necessary to raise or lower the output voltage of the regulator and hence, raise or lower the output voltage of the generator. Such systems employ moving mechanical parts subject to wear, dirt, vibration and related malfunctions.
Some voltage regulating systems prevent the output current from surpassing a preselected maximum level by current limiting. The output current supplied to the load is sensed to detect excessive current conditions. If the regulator senses a low voltage condition, present regulators signal the alternator to demand increased excitation of the alternator in an attempt to increase the voltage output to the load. Additionally, some regulators will respond to effective short circuits, or zero voltage conditions, by shutting down the alternator to guard against abnormal current.
Current regulating systems, while able to increase or decrease excitation levels in the alternator, cannot limit excitation levels to a minimum and a maximum for a safe operating range to prevent damaging the alternator by overheating or creating a loss of synchronism.
Some presently available regulators detect faults in the sensor circuits. A break in a sensing lead or a loose terminal in the sensing circuit effectively opens the circuit causing the regulator to shut down the alternator. In such systems, there is no indication of the cause of a shutdown, e.g., a loss of sensing capability (open circuit) or an overtemperature condition.
In some situations, knowledge of the actual time of service of a regulator is beneficial. Present systems are incapable of making such a measurement.